High electron mobility transistors (HEMTs) have been found to be particularly well suited for high frequency (e.g., radio frequency), high power applications. Some types of HEMTs (e.g., certain gallium nitride (GaN) based HEMTs) include a conductive field plate adjacent to but electrically isolated from the device's gate. The field plate may be electrically coupled to the device's source electrode, for example, and this arrangement may serve to improve device performance by reducing the peak electric field in the transistor. As technologies related to GaN HEMTs continue to develop, device designers continue to seek additional ways for further improving the performance and reliability of such devices.